Many chemical and/or biological analytical instruments that are currently used for sample analysis have many limitations. Some areas that are currently deficient are: the ability to quickly analyze a sample using a compact instrument in a high throughput manner, an efficient and effective sampling method, and an effective manner to interface multiple analytical instruments. A comprehensive instrumental approach can address chemical and/or biological detection issues in many areas/applications such as pharmaceutical, environmental, and food industry, as well as homeland security, in particular home made explosives, liquid detection needs with adaptability to future threats. A comprehensive instrumental approach on ion mobility spectrometer (IMS) apparatus and methods offer all of the following advantages: improved throughput compared to current detection systems; adaptability to new ionization methods that can be used to introduce samples in different categories of chemicals in vapor, liquid and particle forms; enhanced capability for detecting labile chemicals, such as homemade explosives TATP, nitroglycerine and PETN; and an interface to mass spectrometers (MS) that will enhance field performance of future MS based field detection systems.
Ion mobility based spectrometers need to utilize various methods and components to be able to analyze samples in a high throughput manner and/or operate in a portable design. Current ion mobility based spectrometers require complicated mechanically designed parts for construction of the drift tube, whereby each component in the drift tube requires multiple parts and produces an overall high power consumption system. The high power consumption significantly limits the performance of the ion mobility based spectrometer. One aspect of the present invention relates to ion mobility based spectrometer systems for continuous sampling operations, rapid temperature control/temperature gradient analysis, and low power consumption portability.
In practical chemical detection, such as explosive detection, applications, the two major challenges to a given analytical instrument are system effectiveness and readiness. Even though existing IMS based trace detection systems can meet the current throughput requirements at airport checkpoint, these detection systems need to have much higher throughput in order to handle the detection requirements for mass transit applications.
Ion mobility based spectrometers (IMS) and MS utilize various methods to introduce the vapor of a sample into the analysis chamber and/or ionization chamber of the given instrument. For example liquid samples can be injected via a syringe and thermally vaporized. Whereas solid samples are commonly vaporized via thermal desorption. Many different methods can be utilized, the chemical nature of the sample generally influences the method used. Heating samples to elevated temperatures in order to vaporize them can be destructive. Since the currently used methods for heating the samples in an IMS range between 220° C. and 300° C., decomposition can occur at these elevated temperatures. For example, the explosive 1,1-diamino-2,2-dinitroethylene (FOX-7) decomposes at 238° C.